Investments in Unconsolidated Affiliates (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	$ 419.1		$ 321.4
Symetra
Investments in unconsolidated affiliates
Equity in Unrealized Gains (Losses) from Investments in Unconsolidated Affiliates	31.1		(43.6)
Total investments in unconsolidated affiliates	415.5	369.0	317.3	326.0	377.5	381.5
Symetra \| Common shareholders' equity.
Investments in unconsolidated affiliates
Symetra Common Shares excluding unrealized gains (losses)	384.4		360.9
Total investments in unconsolidated affiliates	415.5	369.0	317.3	326.0	350.9	351.2
Symetra \| Warrants
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	0	0	0	0	26.6	30.3
Hamer, LLC
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	$ 3.6		$ 4.1